81 Seca 550 electrical issues! Seeking guidance

Hello! I got a seca 550 a little over a year ago. It ran all last summer but started dying at random moments. I've been working on it and am still experiencing this random cutting out. Was wondering if y'all might have some advice on things I could try before deciding if I should rebuild the whole electrical harness.

Since last summer I've;
removed the side stand kill switch/relay, automatic flasher relay,
cleaned the grounds
new battery
new starter solenoid
new fuses/block
rebuilt the carbs
new pod filters (wish it still had the airbox but at least the new pods are nicer than the previous ones.)
valve shims adjusted
rebuilt front brake caliper
new spark plugs
new run/stop switch

Any idea why it could still be dying? I thought the new starter solenoid might fix it based on the thread I read, but clearly not. when it dies while I'm riding I can usually flip the run/start switch and fire it back up while holding the clutch in. Note: when it dies it is very random! sometimes the bike is warm and I'm cruising, sometimes it's when it's first getting started in the morning. if it starts and dies while warming up it will not start again without starter fluid and about 50% of the time it needs fluid just to get going in the first place. Is there anything I should check?? Is there a thread regarding doing complete electrical rebuilds/checks?

any advice is greatly appreciated, help me get this sweet puppy to stop dying.
Thanks

 

does it just cut out or loose power? how quickly does it restart?
ohm out the ignition system replace the spark plug caps,
are you sure it is not a fuel related problem
Your Gas Cap and You

when you cleaned carbs did you clean out the brass enrichment tube? and the wells it inserts into?



wet set carbs fuel level?

Setting the fuel levels


main source of power
Clean and lube the ignition switch

have you ohmed out and tested the charging system?

specs for above found in this link

The Ultimate Relay, Switch, Sensor, and Diodes Guide

are you sure you are running on all four cylinders? take header temps.


mostly your new battery could be bad. do a voltage drop test when trying to start if it drops below 10 volts it will not start.

 

under the gass tank near the right coil is a black connector the wires runn to the right control (runswitch and starterbutton)
mine was loose and dirty would reconnect when i slaped tank. check it clean it and make it tight.
this could be why your bike quits, my 3 xj550s all had this issue

poor connection of red/white wire would cause voltage drop and no fire condition

 

thanks so much! Just checked the black connector and found something interesting. So the connection looks good however there is a ground going into the connector from the switch that leads nowhere. could this be an issue? also I will defiantly clean the ignition switch, because there appears to be .5 volt drop between the main fuse and ignition switch. Battery seams ok though. It been consistently giving me over 12 volts, however I still need to do the drop test.

 

also just noticed the connector for the regulator is fried

 

the starter switch grounds through the handle bars the wire to nowhere is factory issue

 

check out your charging system there is an ohm out test in link I posted , that connector needs to be cleaned/replaced
is it the regulator connector or the harness connector or both you can just use another connector or connectors to repair

 

voltage OUT PUT 2000RPM s
* 2000+ rpms: 14.2 volts up to about 14.8 volts, with a maximum of 14.8 volts

 

Good morning @blake

If reading this correctly and you are in fact referring to the 4 pin connector for the Off-On-Off switch/Starter button - yes - that was an issue on my XJ550 as well. That little black ground wire is definitely a problem. This was experienced by myself after swapping out the stock chrome ape hangers (creating an earth ground), to some powder coated flat bars (no more earth ground).

My solution to the no start/hanging starter/cutting out was:
1. snipping black ground wire out of the connector
2. Cleaning wire end + little dash of solder
3. Adding eye connector + solder + heat shrink
4. Sanded/cleaned up the coil ground connection and bolted her in.
5. Validate the circuit before attempting to start/run
6. Always be prepared for an electrical fire (wire cutters, fire extinguisher, bike removed from the garage)


I've got some video of this too. Reach out to me with a DM and I can send those videos your way.